# 2nd derivative, is my answer correct

## Homework Statement

The position of a particle moving along the x-axis is given by s(t)=7t^2+33. Use difference quotients to find the velocity v(t) and acceleration a(t).

My textbook says v(t)=s'(t) and a(t)=s''(t). I think I got the answer, but not sure if the velocity should have an x in it. Please reply and let me know.

## The Attempt at a Solution

s(t)=7t^2+33
s'(t)=14x
s''(t)=14

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Where did the x come from?
s(t) = 7t^2 + 33
so by using the power rule s'(t) = 7*2(t(2-1)) = 14t

Sorry I meant t. I was doing a bunch of problems, mostly with x so I got mixed up when I was typing. I meant:

s(t)=7t^2+33
s'(t)=14t
s''(t)=14

[PLAIN]http://calc101.com/Calc101/MSP?MSPStoreID=MSPStore10452429_0&MSPStoreType=image/gif [Broken]

Yes, you are correct.

Last edited by a moderator:
Mark44
Mentor
Sorry I meant t. I was doing a bunch of problems, mostly with x so I got mixed up when I was typing. I meant:

s(t)=7t^2+33
s'(t)=14t
s''(t)=14
These are correct. Did you get s'(t) and s''(t) using difference quotients?